traffic volume study
TRANSCRIPT
Welcome to the Presentationon
Traffic Volume Study
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DEPARTMENT OF CIVIL ENGINEERINGAHSANULLAH UNIVERSITY OF SCIENCE & TECHNOLOGY
COURSE TITTLE : CE 452
COURSE NAME : Transportation Engineering Sessional -2
Course Teacher : Mr. Minhajul Islam Khan & Ms. Nuzhat Azra
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Presented by group 1
Amit Chandra Barman Jyotiram Mallick Shibu
Mohammad SayemMuktarul Kabir
Rafid NewazRifat Ahmed
Sourav TalukderTasneef Ahmed
11.01.03.12511.01.03.10411.01.03.10211.01.03.12311.01.03.12011.01.03.07111.01.03.12411.01.03.098
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Contents• Introduction• General Objectives of Traffic Volume Study• Study Site• Methodology• Survey procedure• Data Collection• Analysis of collected data• Conclusion• Recommendations• Limitations of the Study
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Traffic Survey
Planning And Designing Traffic Facilities
Determining The Need For Traffic Control Devices
Studying The Effectiveness Of Introduced Schemes;
Diagnosing Given Situations And Finding Appropriate solutions;
Forecasting The Effects Of Projected Strategies;
Calibrating And Validating Traffic Models Etc.
Traffic Surveys Are Required To Transportation Engineers For :
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Introduction
Traffic volume studies are conducted to determine the volume of traffic moving on the roads and classifications of roadway vehicles at a particular section during a particular time.
Volumes of a day or an hour can vary greatly, depending on the different day of the week or different time period of a day.
Traffic Volume survey is the determination of the number, movement and classifications of roadway vehicles at a given location.
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Specific Objectives
To determine vehicle composition duringsurvey period
To determine service flow rate in PCU unit
To determine Directional Distribution of traffic
To estimate average daily traffic based on expansion factor
To draw partial flow fluctuation curve
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General Objectives
A. Design Purposes
B. Improvement Purposes
A. Planning Purposes
C. Dynamic Traffic Management Purposes
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A . Design Purposes
Structural and geometric design of pavements, bridge,
and other highway facilities.
Intersection design including minimum turning path,
channelization, flaring, and traffic control devices.
Pedestrian volume study is useful for designing side-walks, pedestrian
crossing etc.
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• To allocate limited maintenance budget rationally, it is important to know the traffic volume carried by a particular roadway section in order to decide the importance of the road and fixing its relative priority.
• In order to improve the roadway operating condition, it is important to know the traffic volume –
• To examine the existing operating/service condition of a roadway section.
• To check the need (warrant) traffic control devices.
• To determine the type of improvement measure need to be taken.
• To measure the effectiveness of a traffic control measure.
B. Improvement Purposes
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Planning Purposes
Accurate information on the amount of traffic on the roads is vital for the planning of both road maintenance and improvement policies
Traffic volume network analysis helps in deciding/planning if there is need for Improvement and Expansion in terms of construction missing links, by-pass, alternative road etc.
Dynamic Traffic Management Purposes
Up to date and continuous flow/congestion information is essential for optimizing - Traffic signal design and thereby improving junction performance and Network productivity by providing information to the road user.
C. Planning Purposes & D. Dynamic Traffic Management Purposes
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Estimation of highway usage andmeasurement of current demand of a facility.
Estimation of trend.
Economic feasibility evaluation.
Computation of accident rates.
Other Purposes
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Scopes of Volume Study
SCOPES
Design
Planning
Improvement
Dynamic Traffic
Management
Estimating Highway
Use
Computing Accident
Rates
Traffic Stream
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Keywords Related To Volume Study
Volume/flow
Rate of flow
Average Daily Traffic (ADT )
Average Annual Daily Traffic (AADT)
Design Hourly Volume
Service flow rate
Directional Distribution
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Methodology
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Main Methods of Counting
• 1. Direct Method
• 2. Indirect MethodManual Counting
Method
• 1. Contact System
• 2. Contact-less SystemAutomatic
Counting Method
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Manual Count Recording Method(Filled Data Sheet and Summary Sheets)
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Figure: Example Manual Intersection
Volume Count Tally Sheet
Tally Sheets
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Car
Bus
Motorbike
CNG
Microbus/
Pajero
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Mechanical Counting Boards
Mechanical count boards consist of counters mounted on a board that record
each direction of travel.
Figure : Manual Counting Board20
Electronic Counting Boards
Figure : Electronic Counting Boards 21
Electronic counting boards are lighter, more compact, and easier to handle. This
is battery-operated, hand-held devices that are light, compact, and easy to handle
compared to tally sheets and mechanical boards
Steps to a manual traffic volume count
1. Prepare :
Determine the type of equipment to use, the field procedures to follow, and the
number of observers required.
Label and organize tally sheets
2. Select observer location(s) :
Observers (data collectors) should be positioned where they have a clear view
of traffic and are safely away from the edge of the roadway.
3. Record observations on site.22
Automatic Counting Method
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Automatic Counting Methods
An automatic survey involves placing a tube or loop across a road
which is connected to a box containing the means for storing the
information.
In this method, vehicles are counted automatically without any human
involvement.
There are two techniques of automatic counting:
a) Contact system based on pneumatic, mechanical, magnetic or
piezo-electric method
b) Contactless system based on electrical/optical, ultrasound/infrared
radar, micro wave, CCTV/video image processing method etc.24
Bending plate
A weight pad attached to a metal plate embedded in the road to measure axel weight
and speed. It is an expensive device and requires alteration to the road bed.
Figure : Bending Plate 25
Pneumatic road tube
Pneumatic road tube sensors send a burst of air pressure along a rubber tube
when a vehicle's tires pass over the tube.
Figure : Pneumatic Road Tube 26
Piezo-electric sensor
A device that is placed in a groove cut into the roadbed of the lane(s) being counted. This
electronic counter can be used to measure weight and speed.
Figure : Piezo-electric Sensor27
Selected Method
Manual Method using hand tally and manual counters
Reasons
• Simple and Direct
• Classified vehicle count can be obtained
• Data can be used immediately after
collection
• No special equipment required
• Not costly• Easy to collect data
Figure : Hand Tally Counter28
Data Collection
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Survey Location
Study Location:Panthapath Road Segment between Russell Square and
Green road-Panthapath Intersection30
Information about Data Collection
Survey Date : 16th January, 2014
Survey route : Pathapath to Russel Square
Method :Manual Method using hand tally and
manual counters
Equipment : Hand Counter , Pencil , Clip Board , Data
Sheets
No. of enumerator : 8 persons
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Equipment Needed
Hand Counter
Supply of blank field data sheets
Pencils , erasers and pencil sharpner
Clip boards.
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RECONNAISSANCE SURVEYS
Reconnaissance survey and route
alignment survey was carried out to acquire
generalized idea about the survey area.
This survey ensures the physical
properties of location which cannot be
authenticated by Google Earth Maps.
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RECONNAISSANCE SURVEYS
Two private hospital, Square Hospital and Shomorita Hospital, is situated alongside
the road . So that traffic attraction is huge in this area.
No foot over bridge in this road .
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Geometric Layout of Intersection
Russel Square Intersection (Units in meter)
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Survey Procedure
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Data Analysis
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Vehicle Composition in Traffic
Stream
Service Flow Rate in PCU/ PCE unit
ADT based on Expansion Factors
Directional distribution
Flow Fluctuation Curves
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Traffic Volume Count DataVehicle Classification Observation in 30 min
Bus 8
CNG 76
Car 329Jeep, Microbus,
Ambulance 78
Motorcycle 89
NMV 245
Utility 20
Truck 0
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Vehicle Composition of Traffic
Stream
1%
9%
39%
9%
11%
29%
2% 0%
Vehicle Composition
Bus
CNG
Car
Jeep
Motorcycle
NMV
Utility
Truck
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Service Flow Rate
Flow Rate
The equivalent hourly rate at which vehicles pass over a given point or
section of a lane or roadway during a given time interval less than 1 hour
usually 15 minutes
Service Flow Rate
It is the equivalent hourly rate at which vehicle pass over a given point or
section of a lane or roadway during a given time interval less than 1 hr,
usually 15 min while maintaining a designated level of service.
Importance of Flow Rate
A short duration count (for e.g. 15 minutes count) can be converted into an
equivalent hourly rate
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Service Flow Rate SERVICE FLOW RATE IN (PCU)
VEHICLE PCU FACTOR FLOW TOTALVEH. IN 30
MINFLOW pcu IN 30
MINSERVICE
FLOW RATEPCU IN 1
HOURBUS 3 8 24 48
CNG 0.5 76 38 76
CAR 1 329 329 658JEEP,
MICROBUS,AMBULANCE
1.5 78 117 234
MOTORCYCLE(MC) 0.25 89 22.25 44.5
NMV 0.5 245 122.5 245
UTILITY 1.5 20 20 40
TOTAL 1345.5
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Service Flow Rate
Service Flow Rate (09:00-09:30AM) 1346 PCU/hr
From calculation it is found that the service flow rate of this corridor at 09:00am to
09:30 am was 1346 PCU/hr. Again, level of service of a road can be determined
from service flow rate. Level of service of a road can be classified according to
service flow rate as below
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LEVEL OF SERVICE VS SERVICE FLOW RATE
According to this table the level of service of Panthapath road was, “E” at 09:00 am-
09:30 am in Thursday.
LOS Service Flow Rate (PCU/hr)A 600B 700C 900D 1200E 1400F >1400
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Directional Distribution (DD)
Directional Distribution
The directional Distribution is defined as the percentage of heavier
volume over the total highway volume.
Importance of Directional Distribution
• Accounts for the directional distribution of traffic
• Used to convert average daily traffic to directional peak hour traffic
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Directional Distribution
Direction Time PCU/hr AveragePCU/hr
DirectionalDistribution
PanthapathTo
Russell Square
9:00 - 9:30 am 13461433 45%
10:30 – 11:00 1405
11:00-11:30 am 1546
Russell SquareTo
Panthapath
9:00 - 9:30 am 18221725 55%
10:30 – 11:00 1672
11.00 – 11.30 1682
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Flow Fluctuation Curve
Flow-fluctuation Curve
Graph of %ADT versus Time usually for a 24 hour period
Importance of Flow-fluctuation Curve
24 hour flow fluctuation curve gives
• Peak Hour Factor (PHF)
• Design Hourly Volume (DHV)
DHV = PHF x ADT
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Flow Fluctuation Curve ( PCU/hr)F
low
Rate
PC
U/A
DT
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Flow Fluctuation Curve (% of ADT vs Time)
Flo
w R
ate
PC
U/H
R
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Flow Fluctuation Curve
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Our analyzed curve is so far different from what a
actual curve looks like. Here, in Figure 5.2
we can see that, usually we get 2 two peak values of
ADT. From the analysis value we get the
maximum ADT from East to West is 5.93% and
maximum ADT from West to East is 5.81% ADT.
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Conclusions
Recommendations
Limitations
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Conclusions
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Scope for Further Study
This volume study was practiced by un-skilled enumerators, which may lead to
some error in data collection process. values are not amenable to easy analysis
by computers
Data collected by manual method of counting, which is unreliable and
irreversible, more representatives and reliable data could be obtained if
automatic data collection method were followed.
For continuous and long term study , maual metod is not suitable.for authentic
value, automatic device is needed.
The composition of traffic stream varies from site to site. Specific vehicular
movements such as left turns, right turns, sraight- aheads etc are not recorded.
Data were collected for short-term (20 minute), which was not representative to
the flow characteristics of the road. If 3days continuous data were collected, that
would me much more representative than this short count of traffic volume.
The ADT and AADT value are not analysed . Short term variations occuring in the
course of a day , and especially the peaking situations in the morning and
evening rush hours are needed for design of traffic control systems are
complicated intersections.54
Limitations of the study
Direct Manual method being less accurate.
More representative results of service flow rate would be obtained if 24
hours volume is counted and the flow-fluctuation curve would show two
distinct peaks around morning and evening rush hours.
Expansion factors used for the calculation of ADT were developed for a
rural primary road.
Proper enforcement of traffic regulation is not obtained.
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Recommendations
This road mainly served the purpose of collector road. Collector roads should
be designed for a level of service C or better.From the data analysis , we can
see the Level of Service is C
The traffic flow is stable with marked restriction
Driver’s selection of speed and reduced ability to pass is reduced. The
volume count must contain more than one cycle to get more authentic value
Manual count method required trained enumerators, which was not available
in this case
For more reliable data automatic data collection process should be used.
Data were collected for 20 minutes by each group, which may not represent
the hourly fluctuation of traffic, so for more allegorical data one hour data
should be taken.
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Thank you.
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